1. Field of the Invention
The present invention relates to a control apparatus of a mobile. More particularly, the present invention relates to a control apparatus of a mobile for the mobile to run in a zigzag manner to work all over a specified region.
2. Description of the Related Art
A robot (one type of mobile) to work within a specified region in every nook and corner is conventionally known. A zigzag travel is generally employed in the control system of such a robot. The zigzag travel is to run back and forth within a specified region at a predetermined interval. This zigzag travel is realized by the combination of a forward operation on a plane and a U-turn operation in reciprocation. The work conducted by the robot includes cleaning, waxing, applying chemical agents, and the like.
FIG. 22 is a diagram for describing an example of the path of the zigzag travel.
A robot 1 starts from a location point "a" to advance ahead by a distance of L.sub.0 in the vertical direction of a work area A. Then, robot 1 turns 90.degree. leftwards and advances at a pitch of p, followed by a 90.degree. turn leftwards. Then, robot 1 moves straight forward L.sub.0 to arrive at location point "b". By repeating the travel of a 90.degree. turn, advance at pitch p, 90.degree. turn and advance of L.sub.0, work area A can be subjected to a working operation leaving no uncovered space.
In such a working operation, there may be an error in the running distance or angle of rotation of robot 1, or difference in the running distance depending upon the state of the floor on which robot 1 runs. In order to eliminate the possibility of an unworked region in the work area, pitch p is determined so that the region worked by robot 1 overlaps in the reciprocating operation.
More specifically, referring to FIG. 23, when the width of the work carried out by one run of robot 1 corresponds to a work width Y, pitch p is set smaller than Y. As a result, a work margin (overlapping width W of work) is produced.
Consider the case where robot 1 is to carry out the work of applying wax. If another coat of wax is applied again on an area where the previously applied wax has dried up, the layer of wax of that overlapping area will become thicker. A step-graded portion will be generated with respect to other areas. In the example of FIG. 23, the work overlapping area (W in FIG. 23) will result in a striation pattern to degrade the quality of the work.
It is therefore necessary to apply the second coat of wax before the underlying wax does not dry up. Furthermore, if reapplication is effected when the underlying wax is half-dried, the glossiness will be lost.
The longest interval in the reapplication of wax is between location points a and b in FIG. 22. Let t.sub.LO be the time required for robot 1 to run straight forward the distance of L.sub.0, tr the time required for robot 1 to rotate 90.degree., and tp the time required for robot 1 to travel the pitch of p. The time required for robot 1 to arrive at location point b from location point a is represented by the following equation (0).
2.times.t.sub.LO +tp+2.times.tr . . . (0)